wifi: mac80211: make 4addr null frames using min_rate for WDS

WDS needs 4addr packets to trigger AP for wlan0.sta creation.
However, the 4addr null frame is sent at a high rate so that
sometimes the AP can't receive it. Switch to using min rate.
Signed-off-by: Lian Chen <lian.chen@mediatek.com>
Link: https://lore.kernel.org/r/20220714091636.59107-1-lian.chen@mediatek.comSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -1207,6 +1207,7 @@ void ieee80211_send_4addr_nullfunc(struct ieee80211_local *local,
 	memcpy(nullfunc->addr4, sdata->vif.addr, ETH_ALEN);
 
 	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+	IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_USE_MINRATE;
 	ieee80211_tx_skb(sdata, skb);
 }